Postoperative sleep disturbance (POSD) is common after breast cancer surgery. In a randomized trial of 100 patients, intraoperative infusion of esketamine combined with dexmedetomidine did not significantly reduce the incidence of POSD compared to control or either drug alone over the first three days. However, on postoperative day 3, each drug alone reduced POSD risk when the other was absent. Dexmedetomidine decreased rapid eye movement (REM) sleep on day 1, while esketamine reduced nighttime awakening time on days 1 and 3. The combination showed no added benefit for POSD, but each drug had distinct effects on sleep architecture.
Hippocampal ripples, brief synchronized electrical events in the brain, are known to support navigation in rodents and short-term memory in humans. This study shows that ripples also increase in the human hippocampus just before people recall recent or remote autobiographical events and semantic facts. Ripple patterns across different hippocampal sites were specific to the type of memory being retrieved. Over time, ripple patterns for autobiographical memories became more similar to those for semantic memory, suggesting a process of semantization. During recollection, ripple-coupled activity was widespread across the neocortex, especially in the default mode network, indicating that hippocampal ripples help coordinate communication between the hippocampus and large-scale cortical networks involved in conscious recall.